A corpora



F. E. CRAWFORD.

ALARM SYSTEM. APPLICATION FILED AuG.I`z. 1918.

1,418,628. PatentedJune 6,1922.

f3' /z W05 a I UNITED STATES PATENT OFFICE.

FRANKLIN E. CRAWFORD, `OF WINCI-IESTER, MASSACHUSETTS, ASSIG-NOR TO BANKERS ELECTRIC PROTECTIVE ASSOCIATION, OF BOSTON, MASSACHUSETTS, A CORPORA- TION OF MASSACHUSETTS.

ALARM SYSTEM.

Application' filed August 12, 1918.

l/ 'o all who-mr t may concern.'

Be it known that I, FRANKLIN E. CRAW- Fono, a citizen of the United States, and resident of `Winchester, in the county of Middlesex and State of Massachusetts, have invented new and Vuseful Improvements in Alarm Systems, of which the following is a specication. Y

This invention relates to an electric signal or alarm system, and particularly to an alarm system for the protection of buildings. The system comprises, generally, an alarm station, one or more control stations, and electrical connections therebetween, each control station being equipped with means normally tending, unless prevented or Testrained, to cause the alarm or signal to be given at the .alarm station, but so long as thus prevented or restrained, leaving the alarm inactive. While thev system might be used for other purposes, it is designed primarily as a watchmans alarm system, wherein the alarm station is connected to one or more controlling stations or watchmans stat-ions, which are fitted with manuv ually operated mechanism adapted to preshown at 1.

vent the giving of the alarm at the alarm station so long as said mechanism is operated manually at predetermined intervals, but which will automatically give the alarm if they are not properly operated manually before the expiration of such intervals.

The accompanying drawings illustrate diagrammatically an exempliiicationof the invention designed for a watchmans alarm system.

The main control circuit of the system is The alarm station or signal station 2 includes a balanced relay or galvanometer 3, or some other electrical device which will respond to variations or interruptions of the current passing through the main control circuit of the system. The alarm or signal circuit 4, which is controlled by said responsive device, is a local circuit and has its own Vindependent battery 5l within the housing of the alarm station. The circuit 4 includes the needle or other moving part of the responsive device 3, the contacts at each side of the needle, and the electric bell, or alarm proper, 6. When the alarm circuit 4 is energized by closing the circuit at .the balanced relay 3, the alarm will be given.

Specification of Letters Patent.

Patented June 6, 1922.

serial No. 249,376.

The main control circuit l is a closed circuit, energized by a battery 7, or other suitable source of electric energy. The current passing through the coils of the responsive device 3, normally holds the needle between its contacts, thereby maintaining the alarm circuit open and preventing the alarm from sounding.

If now the current in main control circuit 1 is interrupted, or substantially reduced, through the coils of the responsive device 3, the needle of the responsive device, which is held open by said coils, will immediately close the alarm circuit 4 and sound the alarm. It will be understood that the alarm station may be situated in the building where the system is installed, or on the outside of the building, or at some remote point such as a police station or other office where there is a person on duty to respond to the alarm.

The main control circuit 1 is suitably arranged within the building to be protected, and isprovidedwith a series of control station circuits 8, 9, 10 and 11, all of which are normally open. If any one of said con-1 trol station circuits should be closed, the current -in main control circuit 1 would be short-circuited, wholly or partly de-energizing thecoils at the responsivedevice 3, and causing the alarm to be given. In each such circuit, 8, 9,v etc., is a normally open switch, 12, and a clock or time-governed switch-closer, 13. Each clock 13 and switch 12 constitutes a control station to be operated by the watchman, and is preferably enclosed in a suitable boX or cabinet 14. One such station is situated at each place in the building where it is the duty of the watchman to report. There may of course be as many stations as desired, and they may be at any locations desired, so long as each is in a circuit capable of short-circuiting the responsive device 3, or otherwise causing it to operate the alarm.

The several time controlled switch-closers 13 are of the kind designed to be wound up or set by hand, and automatically to close their respective switches within a predetermined period of time thereafter unless they are re wound or reset before such operation takes place. In practice they are set to operate successively at such intervals that the watchman will have time in going his rounds to visit each boX, reset it, and get back to it after visiting and manipulating all the other stations in the series, and before it closes its switch.

H, for example there are four ivatchmans stations in different parts of a building or plant, at each of which it is the duty of the Watchman to report once an hour, each time piece will be designed to close its switch automatically one hour after being Wound up or set; and the several time pieces will be started so as to operate l5 minutes apart, or at other convenientintervals. The Watchman then visits the boX at station No. l Within the hour -and Winds it up or resets it, so that for another hour it Will not close its switch. He then proceeds to the box at station No. 2 performing the same operation, and So on throughout the series, returning to the irst station in time to prevent the switch there from closing. lt through neglect or accident, or foul play, he should omit to reset the time piece at any station, the clock Would automatically close the switch 12, thereby short-circuiting the coil at the responsive device 3 and causing the alarm to be given. As there are several stations in the system, the interval between the times when any given station and the next succeeding station must be manually operated by the Watchman is comparatively short, and

notice is therefore promptly given of any failure in the performance of his duty.

I claim:

l. In an electric signal system of the kind described, an alarm station, a remote controlling station, a normally closed controlling circuit therebetween, and automatically operating means at the controlling station normally tending, unless mechanically restrained, to cause the circuit to be broken and the alarm to be given.

2. In an electric signal system of the kind described an alarm station, a controlling station, a normally closed controlling circuit therebetween, and means at the controlling station adapted automatically to cause the alarm to be given at a predetermined period ot time, and also adapted to be manually operated to prevent such alarm.

3. In an electric signal system of the kind described, an alarm station, a controlling station, a controlling circuit therebetween, a current varying device at the controlling station adapted to control the alarm, and a time-piece to operate said device at a predetermined period of time, said time-piece being manually operable to prevent the operation of said device.

et. In an electric signal system of the kind described, an alarm station, a closed main controlling circuit normally adapted to maintain the alarm inactive, a station circuit adapted when operated to interrupt the current through the main controlling circuit, and a controlling station in said station circuit comprising mechanism adapted automatically vto operate the station circuit and interrupt said main circuit at a predetermined period of time, and manually operable to prevent such interruption.

5. In an electric signal system of the kind described, an alarm station, a main controlling circuit normally adapted to maintain the alarm inactive, a station circuit adapted When operated to vary the current through the main controlling circuit, and a controlling station in said station circuit comprising mechanism adapted automatically to operate the station circuit and vary said main circuit at a predetermined period of time, and manually operable to prevent such van riation.

Signed by me at Boston, llassachusetts, this second day of' August, 1918.

` FRANKLN E. CRAFORD. 

